KQueue and EVFILT_TIMER question

Mel fbsd.questions at rachie.is-a-geek.net
Wed Feb 20 23:45:48 UTC 2008


I'm using a kqueue(2) that installs a timer into the queue when a certain 
condition has happened. This timer waits for another condition at intervals 
(specifically, it watches for a file to be created). Every 500ms it does a 
stat(2) for a given filename and when stat succeeds, I do the following:

changes[0].flags |= EV_ONESHOT;
changes[0].udata = (void*)1;
changes[0].flags |= EV_ADD;

Problem is, that this timer now never disappears, even if I replace changes[0] 
with a completely different event (specifically, EVFILT_VNODE on the file we 
now know is created).
I suspect that:

"This filter automatically sets the EV_CLEAR flag internally." is the culprit. 

So how would I go about terminating the timer? Or is the only way to 
initialize it as EV_ONESHOT and keep reinstalling a new one when required? Or 
close the kq all together and start a new one? EV_DELETE?

On a related note, is the ident for a timer really used and should I increment 
it (all examples I've seen simply set ident to 1).

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